What happened about 2,017 years ago?

This raises a very good point. And it’s got me wondering. It’s 2017 in Pakistan, Saudia Arabia, & all Nations is it not? If Islam doesn’t believe our God is real and only views Jesus as a mere prophet, then why do they recognize the birth of God’s son in time? If Muhammad was the “chosen one” why then don’t we acknowledge his birth? All Nations recognize this year as being 2017. It’s just very interesting.